Pitman for vacuum pumps and the like



Aug. 31 1926,

l. S. PURCELL ?I'1'-IlAN'FOR VACUUM PUMPS AND THE LIKE Filgd Nov. 14, 1925 Patented Aug. 31, 1926.

UNITED STATES ISAAC S. PUB-CELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO C. BAY COMPANY, OF

BLUFFTON, INDIANA, A CORPORATION OF ILLINOIS.

PITMAN FOR, VACUUM Application filed November The invention relates to a pitman especially adapted for use in pumps such as are employed in player pianos; and the primary object of the invention is to provide a pitman of advantageous construction having provision for taking up wear at the bearings so as to insure long life coupled with smooth and quiet operation.

A general object of the invention is to produce a pitman of this character which is simple in construction, light in weight, and efiicient in operation, and which does not require lubrication at the bearings.

In the manufacture of vacuum pumps for player pianos, a frequent source of trouble and annoyance is encountered in the operative connection between the motor driven shaft and the several bellows units. Thus it is essential from a practical standpoint that the pump shall be capable of operating over a long period of time substantially noiselessly, and that the pitman bearings shall not require lubrication notwithstanding the fact that they are subject to severe wear. I attain these results by constructing the pitmen which connect the bellows units with the driven shaft, in the form of rigid links having opposite .hooked ends providing recesses for receiving segmental bearing blocks of a suitable material partially surrounding the pivot pins and retained by an intermediate or interposed spring member also having bent ends but arranged in opposed relation to said hooked ends, said spring member further operating to take up any wear on the bearing memhere.

In the accompanying drawings, I have illustrated my invention in its preferred form as applied to a vacuum pump of a player piano, but it will be understood that the invention is not limited to the particular application illustrated nor to the construction and arrangement shown and described except as may be necessitated by the state of the prior art in the interpretation of the appended claims.

Figure 1 of the drawings is a front elevational. view of a pump of the type commonly employed in player pianos and having pitmen embodied therein constructed in accordance with my'invention.

Fig. 2 is a fragmentary elevational view with one of the pitmen in section, the view being drawn on a larger scale.

PUJHYS AND THE LIKE.

14, 1925. Seria1.1\To. 69,072.

Fig. 3 is a detail sectional view taken approximately in the plane of line 33 of Fig. 2

Figs. 4 and 5 are perspective views of the main link member and the spring member respectively.

Referring first to Fig. 1, the vacuum pump to which my invention is applied comprises generally a plurality of bellows units 7 enclosed within a box or frame 8 and equipped with suitable valve means in a manner well known in the art. 9 designates a shaft driven by means of an electric motor or the like (not shown) and having a crank arm 10 carrying a crank pin 11 on which is mounted a spider 12 operativelyconnected with the several bellows units by pitmen generally designated by the numeral 13.

The spider-'12 has four arms 14 each of which has a pivot pin 15 near its free end with which one end of a pitman 13 is con nected. and the movable board 16 of each of the bellows units carries near its free end a bracket 17 having a pivot pin 18 projecting from one side thereof with which the other end of the pitman is connected.

Each of the pitmen 18 comprises a main or link member 19, herein shown in the form of a flat narrow bar of sufficient thickness to insure rigidity. At its opposite ends this bar is hooked to provide recesses 29 adapted to receive a pair of segmental bearing blocks 21 disposed on opposite sides of the pivot pins 15 and 18 respectively. The bearing blocks 21 are so proportioned as to constitute slightly less than a semi circle so that when fitting about their pivot pins a slight space is left between them for wear takenp purposes.

To retain the pairs of bearing blocks 21 in their respective recesses 20, and to take up the wear on the bearing blocks, I employ a spring member 22 slidably bearing near its opposite ends upon the member 19 and having bent ends 23 shaped to conform to the curvature of the bearing blocks. In its n'iid-portion the spring member 22 is bowed away from the member 19 as indicated at 24:, the arrangement being such that this intermediate bowed portion constitutes a spring acting tov cause the bent ends 23 to exert prcssui' e upon the bearing blocks in order not only to retain themin their recesses 20 but to take up any wear ocourrlng about the pivot pm. At the same time, the bowed.

spring portion 24 of the member 22 is of such stiffness as to be capable of withstanding the outward thrust in the operation of collapsing the bellows units, the force required for this purpose being relatively small.

Each of the spring members 22 is retained in operative relation to the link member 19 by an interlocking engagement between it and the link member. This is provided for by a lug 25 at each end of the member 22 engaging in a notch 26 in the corresponding end of the member 19. Suitable washers 27 and cotter pins 28 may be provided to retain the ends of the pitman in operative relation to the pivot pins 15 and 16.

The bearing block 21 may be made of any suitable or preferred material such, for example, as hard maple specially treated so that it is unnecessary to supply lubricant to the bearings in use.

It will be observed that my improved pitman construction provides a positive connection between the pivot pins in the direction in, which the power is applied to the bellows units, that is to say. in the direction of pull upon the bellows units. The force required to be applied in the opposite direction (the pushing force) being relatively slight, and the spring member 22 being stifi', the members 22 are, capable of transmitting it without yielding. At 'the same time, the member 22 through the action of the intermediate bowed portion 24, exerts ample pressure upon the bearing members 21 to retain them snugly within the recesses 20 while taking up any wear occurring about the pivot pins. The constrnction thus provided is relatively simple. light in weight, and it has been found extremely durable.

I claim as my invention 1. In a pump for player pianos, the combination ot a plurality of bellows units and a driven member, of means for pivotally connecting said member with each of said units comprising a rigid link member, pivot pins on the bellows unit and driven me1nber respectively, pairs of bearing members of wood or the like mounted in opposite ends of said link member, the latter having recesses at its opposite ends to receive said bearings. and means including a power transmitting sprlng acting to retain the bearing members 1n their respectlve recesses and in snugly fitting relation to their respective pivot pins, said spring being made of such stiffness as to transmit without yielding power from the driven member to the bellows unit in a direction to collapse the unit.

A pitman for pumps and the like comprising, in combination with a pair of pivot pins to be connected, a rigid member havform of a thin strip of: metal having ing opposite ends providing recesses, seg mental bearing members fitting in said recesses and disposed on opposite sides the pivot pins, and a spring member in the bent ends coasting with said recessed ends of the link member to retain the bearing members in their said recesses and in snugly fitting relation to their respective pivot pins.

3, A pitman for pumps and the like com prising, in combination with a pair of pivot pins to be connected, a rigid link member in the form of an elongated bar having its opposite ends bent to term recesses, pairs of bearing: members in the respective recesses arranged about said pivot pins, and an elongated relatively thin metallic strip having opposite ends bent to engage with the bearing); members in opposed relation to the bent ends of the link member.

l. A pitman for pumps and the like comprising, in combination with a pair of pivot pins to be connected, a rigid link member in the form of an elongated bar having its opposite ends shaped to form recesses, pairs of bearing members in the respective recesses arranged about said pivot pins, and an elongatec relativelv thin metallic strip having), opposite ends bent to engage with the bearing members in opposed relation to the ends of the link member, said strip having intermediate bowed portions acting to exert spring pressure upon the respective bearing members.

5. A. pitman for pumps and the like comprising, in combination with a pair of pivot pins to be connected, a rigid link member in the form ofan elongated bar having its opposite ends bent to form recesses, pairs of bearing; members in the respective recesses arranged about said pivot pins, and an elongated relatively thin metallic strip having; opposite ends bent to engage with the bearing members in opposed relation to the bent ends of the link member, the bent ends of said link member and of said strip having an interlocking: engagement to maintain them in operative relation.

6. A pitman of the class described comprising a pair of elongated members arranged in substantially parallel relation and having their opposite ends shaped to receive bearing blocks between them, one of said. members being rigid and the other being bent to provide a stiff spring. portion tending! to produce a relatively slight movement of separation between its ends which is restrained by the rigid member.

7. A pitman of the class described comprising a pair of elongated members arranged in substantially parallel relation and having their opposite ends bent to receive bearing blocks between them. one of said members being rigid and the other being bent to provide a spring portion hetween its ends tending to produce a movement of separation between said bearings which is restrained by the rigid member, said members being adapted to interengage at their opposite ends to prevent relative lateral movement between them.

8. A pit-man of the class described comprising a pair of elongated members arranged in parallel relation and having their opposite ends bent to receive bearing blocks between them, one of said members including a spring acting to effect a movement of separation between the bearings, and the other of said members being rigid and ISAAC S. PURCELL. 

